1. Scope of Invention
This invention relates generally to in-line fans, and more particularly to redirecting vanes within the housing of in-line fans of the centrifugal impeller type for enhanced air flow and efficiency.
2. Prior Art
Conventional in-line or duct-type centrifugal impeller-type air flow fans are well known in the art. These fans include a motorized centrifugal impeller assembly positioned centrally within the fan housing between inlet and the outlet thereof. Typically, the housing is enlarged in the central portion thereof to accommodate the desired size and performance of the centrifugal impeller and reduced in diameter at the inlet and the outlet thereof for conduit or duct connection.
Because of the competitive nature of the market for such in-line fans, designers and manufacturers are continually looking for improved efficiency and/or increased air flow produced by these fans. Great effort and sophistication in design have been expended in empirically and theoretically designing the cross section and orientation of these centrifugal impeller blades. However, applicant is unaware of any effort directed to housing additions which achieve the objectives of improved efficiency and air flow by additions to the interior of the housing radially outwardly adjacent to the centrifugal impeller itself.
The present invention is directed to improvements in centrifugal impeller-type in-line fans with the addition of selected numbers and shapes of vanes positioned radially outward from the impeller and which are intended to reduce the swirl or rotation produced by the impeller before the air flow is discharged from the outlet of the housing.
This invention is directed to an in-line fan including a housing having an inlet and an outlet spaced apart and substantially coaxial one to another and a motorized centrifugal-type impeller mounted centrally within the housing substantially coaxially between the inlet and the outlet. A plurality of spaced air flow redirecting vanes are each connected to and radially extend inwardly from an inner surface of said housing toward, but not to, a radially outermost perimeter of the impeller whereby air flow through said housing is increased by the vanes. Various vane configurations, clearances and number of vanes are disclosed.
It is therefore an object of this invention to provide increases in efficiency and air flow of conventional centrifugal impeller-type in-line fans.
It is another object of this invention to enhance air flow through centrifugal impeller-type axial fans by the addition of selected numbers and configurations of fixed air flow redirecting vanes extending within the housing between the housing inner surface and the outer periphery of the centrifugal impeller.
It is another object of this invention to reduce noise emanating from centrifugal impeller-type axial fans by the addition of selected numbers and configurations of fixed air flow redirecting vanes extending within the housing between the housing inner surface and the outer periphery of the centrifugal impeller.
In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with reference to the accompanying drawings.